Ultrathin and uniform barrier layer for coated cellulosic structures

Patent metadata

Field	Value
Publication number	US-2025320664-A1
Application number	US-202519050716-A
Country	US
Kind code	A1
Filing date	Feb 11, 2025
Priority date	Feb 13, 2024
Publication date	Oct 16, 2025
Grant date	—

Abstract

A coated cellulosic structure includes a cellulosic sheet substrate, a basecoat layer on the cellulosic sheet substrate, and a barrier layer on the basecoat layer. The barrier layer has an average thickness (AT) in a range of from about 1 μm to about 6 μm. The barrier layer has a uniformity in thickness characterized by a coefficient of variation (CV) of 0.7 or less, wherein CV=σ/AT, wherein σ is the standard deviation of the thickness.

First claim

What is claimed is:

1 . A coated cellulosic structure, comprising:
a cellulosic sheet substrate; a basecoat layer on the cellulosic sheet substrate; and a barrier layer on the basecoat layer, wherein the barrier layer has an average thickness (AT) in a range of from about 1 μm to about 6 μm, and wherein the barrier layer has a uniformity in thickness characterized by a coefficient of variation (CV) of 0.7 or less, wherein CV=σ/AT, wherein σ is a standard deviation of the thickness.

2 . The coated cellulosic structure of claim 1 , wherein the cellulosic sheet substrate comprises bleached fibers.

3 . The coated cellulosic structure of claim 1 , wherein the cellulosic sheet substrate comprises natural kraft fibers.

4 . The coated cellulosic structure of claim 1 , wherein the cellulosic sheet substrate comprises recycled fibers.

5 . The coated cellulosic structure of claim 1 , wherein the cellulosic sheet substrate has a thickness ranging from about 6 to about 36 points.

6 . The coated cellulosic structure of claim 1 , wherein the basecoat layer comprises a polymer binder and mineral pigments.

7 . The coated cellulosic structure of claim 6 , wherein the basecoat layer comprises a binder to pigment ratio ranging from about 12 to about 50 parts binder to 100 parts pigment.

8 . The coated cellulosic structure of claim 1 , wherein the barrier layer comprises an aqueous based formulation.

9 . The coated cellulosic structure of claim 8 , wherein the aqueous based formulation comprises at least one of a polymer latex, a polymer dispersion, and a polymer emulsion.

10 . The coated cellulosic structure of claim 8 , wherein the barrier layer comprises pigments.

11 . The coated cellulosic structure of claim 10 , wherein the pigments in the barrier layer comprise at least one of clay and calcium carbonate.

12 . The coated cellulosic structure of claim 10 , wherein the barrier layer comprises a binder to pigment ratio ranging from about 150 to about 900 parts binder to 100 parts pigment.

13 . The coated cellulosic structure of claim 1 , wherein the coated cellulosic structure further comprises a second layer of the barrier coating.

14 . The coated cellulosic structure of claim 1 , wherein the barrier layer is applied to achieve a Water Vapor Transmission Rate (WVTR) of less than 400 grams/m 2 /day at 38° C. and 90% RH.

15 . The coated cellulosic structure of claim 1 , wherein the barrier layer provides an Oil and Grease Resistance (OGR) meeting a Kit level of at least 12.

16 . A method for applying a barrier layer to a basecoated cellulosic structure, the method comprising:
transferring a barrier material to a roller having cells for holding a predetermined volume of the barrier material; transferring the barrier material from the roller having cells to a transfer roller; applying the barrier material from the transfer roller to a basecoat layer on a cellulosic sheet substrate to form a barrier layer; and drying the applied barrier layer at a drying temperature of 200 degrees F. or greater for a time sufficient to achieve a web surface temperature of 120 degrees F. or greater.

17 . The method of claim 16 , wherein the applied barrier layer is at the drying temperature for at least 6 seconds.

18 . The method of claim 16 , wherein the drying temperature is in a range of 200 to 350 degrees Fahrenheit.

19 . The method of claim 16 , wherein the web surface temperature is in a range of 120 to 180 degrees Fahrenheit.

20 . (canceled)

21 . (canceled)

22 . (canceled)

23 . (canceled)

24 . A method for manufacturing a coated cellulosic structure, the method comprising:
providing a cellulosic sheet substrate; applying a basecoat layer on the cellulosic sheet substrate; and applying a barrier layer on the basecoat layer, wherein applying the barrier layer comprises: transferring a barrier material to a roller having cells for holding a predetermined volume of the barrier material; transferring the barrier material from the roller having cells to a transfer roller; applying the barrier material from the transfer roller to the basecoat layer to form a barrier layer; drying the applied barrier layer at a drying temperature of 200 degrees F. or greater for a time sufficient to achieve a web surface temperature of 120 degrees F. or greater.

Assignees

• Westrock Mwv Llc

Inventors

• Savoji Mohammadtaghi
• Bell Malik Anson
• Pang Jiebin

Classifications

• B05D7/52

  Two layers · CPC title

• B05D3/0254

  After-treatment · CPC title

• B05D2203/22

  Paper or cardboard · CPC title

• B05D1/28

  performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers · CPC title

• D21H19/54

  Starch · CPC title